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For the past several years my 20 year old LX186 has started failing after an hour or so of mowing. Running along just fine then it dies very quickly (few seconds). Waiting 30 min and it starts quickly and will run a while longer then die again.

At time engine dies, the normally full fuel filter is empty. Bubbles can be seen coming up the gas line as it attaches to the filter. It is quite warm, hot, in the engine compartment at time engine dies. Engine is just not getting fuel.. buy why?

I've checked the fuel tank cover - vent is working and loosening it greatly does not prevent problem. I have verified good airflow over the engine - have flushed out the path cooling air takes.

Engine oil is changed on schedule as is air filter & cleaner. Engine runs smoothly with lots of power from cold to just before engine dies.

I'm using regular unleaded gas from Kwik Trip - have for years- it is not "supposed" to have any ethanol in it, but since I observe bubbling in the line only when the fuel line get hot, ethanol boiling could be a possibility.

Fuel pump seems to be working fine, it is just not getting liquid gas in the fuel filter to pump. I noticed the vent(?) on the side of the fuel pump has a hole that has many brass pins in it. I assume that is a vent of some kind. It may have dirt/dust in between the pins. Is that anything to worry about? Could it be the pump is not pulling fuel as well when it gets hot?

Any suggestions would be most welcome!

It sounds like a fuel pump problem. Three things I would check first. Make sure you have a fuel filter designed to be used with a fuel pump. Make sure that the pulse line to the pump is not spongie, allowing it to expand with heat. As soon as it happens the next time, remove the line from the pump to the carb and turn the engine over. If no fuel comes out of the pump we know it is either bad pulse line, bad pump or obstruction in the tank.

This reminds me of a car years ago. It had a small dia plastic supply line. I chased a starvation problem for months. Finally opened the tank-line connection. The line was choked with some kind of white debris. Apparently at low demand the bowl could fill up, but enrichment (throttle) depleted the fuel level. Try running a probe through the line both ways, with air blast. Do you dope your gas or drain for winter? Try cutting open the inline filter and have a look.

Well, folks, I think I've solved the problem. I'll post this here incase someone else experiences this problem.

I went to my local JD dealer and they said, before you bring it in for service, try blowing out the gas line. That didn't make sense to me because the mower ran great for the first 45 min at high speed, then it would die till it cooled off. So, just to humor the dealer, I removed the fuel line from the filter intake, hooked up my air compressor and blew air through the fuel line. Lots of bubbles came up in the fuel tank. I blew it out good.... then hooked the line back up to the filter.

Gosh darned if I've cut the grass about 5 times since then.. about 2 hrs/cutting... and no engine death! Could this have really fixed my problem? Seems like that is a real possibility!

Alfred622 said:

Well, folks, I think I've solved the problem. I'll post this here incase someone else experiences this problem.

I went to my local JD dealer and they said, before you bring it in for service, try blowing out the gas line. That didn't make sense to me because the mower ran great for the first 45 min at high speed, then it would die till it cooled off. So, just to humor the dealer, I removed the fuel line from the filter intake, hooked up my air compressor and blew air through the fuel line. Lots of bubbles came up in the fuel tank. I blew it out good.... then hooked the line back up to the filter.

Gosh darned if I've cut the grass about 5 times since then.. about 2 hrs/cutting... and no engine death! Could this have really fixed my problem? Seems like that is a real possibility!

Click to expand...

Thanks for replying with a follow up answer.

I firmly believe fuel lines should be replaced with new every few years ( 10 at most ) if nothing more than deterring fire hazards . I believe you got lucky for 10 years .

If you blew the debris back into the fuel tank (you mentioned bubbles), you are doomed to repeat this problem unless you've already cleaned the fuel tank

i have a john deere lx 186 17.5 hp low oil press light is and want go out,ihave change oil & filter & if you take off the smiss unit the light still on went to john deere shop & they told me some things but them work need all the help to solve this problem

JD, This should have its own thread. It seems lost here. You are chasing A. real problem or B. false negative. What I would do is buy a cheap mechanical oil pressure gauge and hook it up for a referee test. They can be bought for less than $10 on line (still, I think) at ?ebay or JC Whit. Mechanical means you will put a tube fitting into the sending source (threaded 1/8" NPT?) The fitting kit comes with the gauge. Start the engine without mounting the gauge. If you see 15 psi at idle and 30-40 psi in run you probably have a bad oil sending switch , original gauge, or ground problem. If low oil pressure also on the mech gauge it may be worn bearings , crank journal or blockage in the oil gallery, damaged oil pump:2cents:.